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Ideas for a new setup

Posted: Wed Oct 21, 2015 5:59 pm
by jonstfrancis
I've been planning a new set up for my aquarium and have been wondering what is realistic or not.
One thing, is polystyrene safe in a tank? I was planning on making a stack of stones but thought all stones would maybe be too heavy and that polystyrene at the top would make the design lighter. I would anchor it in with a long piece of river wood.
Second, has anyone used silicon to glue rocks to the tank base? I thought to glue stones all over the bottom and then sprinkle sand and gravel between the gaps and hollows: Making a realistic river bed. I thought it would aid in cleaning as dirt wouldn't accumulate under the stones. Is it a good idea or am I missing something?

Re: Ideas for a new setup

Posted: Thu Oct 22, 2015 2:52 am
by Bas Pels
I have polystyrene in a ot of tanks under the sand. In one tank it has been in use for almost 12 years now (it was made on 4 October 2003 and filled it 3 weeks later) this polystyrene will have to be replaced though, it has been too lonig in the water. On top of the polystyrene I have some tiles, to protect is. And to keep it from floating in case the sand layer gets too thin

But I never ever saw any adverse effect

Regarding glueing stones - I would not do it. I tend to have reasons to net fishes every 18 months or so, and that implies remouving all the stones and so on. Some weigh close to 30 kilos, and then I am very happy I only have to lift one.

I put the lowest stones on the tiles, and then I build further. But the stones are large, longer than 1/3 of the height of the tank, and experience tought me not to use more than 3 layers.

I would not start with a piece of wood - sones on wood never look natural. First stones, and you can - and often should - top it off with wood

Re: Ideas for a new setup

Posted: Fri Oct 23, 2015 4:13 am
by jonstfrancis
Thanks for your thoughts Bas Pels,
The piece of wood was to be at the very top of the stones whether I incorporated polystyrene or not.
Why do you place polystyrene on the bottom of the tank? Is that to protect the glass from when you place stones in there?

Re: Ideas for a new setup

Posted: Fri Oct 23, 2015 7:46 am
by Bas Pels
Precisely. And as I don't know exactly where to put the rocks - and I like to have a feww close to the frons screen, in order to make the tank look deeper than it is, I put it everywhere

Re: Ideas for a new setup

Posted: Mon Dec 14, 2015 9:28 pm
by Diana
Silicone does not glue rocks together very well. I made a pretty neat arrangement several years ago. Then changed it, and removed the siliconed rocks after a year or two. A few are still stuck together, but most fell apart while still in the tank.

There are better adhesives for aquarium use.

A material sold in the lighting department of many hardware stores called Egg Crate is often used under rocks to distribute the weight better across the floor of the tank. It is made for ceiling lights. Google an image using the term Egg Crate Light Diffuser.
With a little care it can be cut to fit the tank (cut it a bit smaller so it is not resting on the silicone sealing the corners of the tank).

Re: Ideas for a new setup

Posted: Thu Dec 17, 2015 12:11 pm
by jonstfrancis
Thanks Diana, I've decided not to glue any rocks or polystyrene together and your experience has confirmed it for me. The egg crate looks useful but I'm still thinking of some way of sealing stones to the aquarium base. The main reason is so that no dirt can accumulate under them and I can use the fixed stones to anchor some pieces of wood without needing lots of substrate.

Even if silicon lost its adhesion to the stones it would still work as a cushioning and stop dirt? If it kept its adhesion all the better. These stones are very tough and smooth, being sea worn granite.

Has no one ever done this? Is it a bad idea?

Re: Ideas for a new setup

Posted: Sat Dec 19, 2015 9:41 am
by Diana
Expanding foam filler works great for attaching rocks to the floor of the tank, and sealing them so no substrate gets under there. It is also a little bit of a cushion so that the rock is not focusing all its weight on one point. I use it to make retaining walls, building the walls out of stone with the filler as mortar. Does a great job of keeping the substrate up on the higher side of the wall.
Expanding foam is available in black, which looks just fine in a tank, especially if you use it with some care so it does not show much. It looks like the shadows between and under the rocks when it is used right.
It can be rather messy, so go slow, and make sure to put it only where you want it. It is almost impossible to clean up when it is wet, if it gets in the wrong spot. When it is dry it can be scraped off perhaps 99%.

If you search using the term Waterfall Foam you should see it, perhaps find a place near you.

Great Stuff makes both the yellow (construction) foam and the black foam.
I have used the yellow material in a tank with tan-brown substrate and similar colored rock, also in my pond (in a hidden location). Works just fine, fish safe.
Some specialty companies like Aquascape that specialize in pond supplies also have their name on the black material. I am sure they are not manufacturing it, though. Aquascape's product is the one I have used in aquariums and ponds.
Touch 'n' Foam is another brand name. I have not used this one.

Re: Ideas for a new setup

Posted: Sun Dec 20, 2015 8:18 pm
by jonstfrancis
Thank you Diana, that sounds great!
Is it easy to use though? How should I do it? Should I squeeze some in a puddle and place the stone on top straight away? I'm interested in how you did it with "keeping the substrate up on the higher side of the wall." Is it worth putting some down and then coating it in sand to hide it?

Re: Ideas for a new setup

Posted: Tue Dec 22, 2015 9:23 am
by Diana
1) Lay out the rocks in a way that works. Strongest structure is to lay them out in overlapping courses, like a running bond pattern in bricks.
2) Put a thin line of EFF on the tank floor where I want to build the retaining wall, then install the first course of rocks. The foam expands, but does not lift the rocks (not much foam, heavy rocks. If you use smaller rocks the foam is strong enough to move them as it expands. Push them back into place). It oozes sideways and fills the gaps between the rocks. This first course will mostly be hidden by substrate, low in front, higher in back, but hidden, anyway. I might use ugly rocks in this first course if they mesh together better, and provide the best base for the next course.
3) Put substrate behind the wall, level with the top of the rocks. Careful not to put any in gaps between the rocks.
4) Put a thin line of EFF along the top of the rocks, especially in the gaps between the rocks.
5) Add another course of stone while the EFF is still wet. As above, it will expand to fill the spaces between the rocks, and it will help stick the rocks together. If the foam is not expanding enough (did not use enough foam) to fill the gaps between the rocks, then add a bit more foam at the back of the wall.
6) Repeat 3, 4, 5 until wall is high enough.

The EFF is not intended to show. Where it does ooze out too much you could stick a few little rocks between the big ones. It skins over pretty fast, does not take sand very well, in my experience. I use the black one because it sort of hides in the shaded spaces between the rocks. It can be cut away if it gets too far into view.

Re: Ideas for a new setup

Posted: Tue Dec 22, 2015 9:03 pm
by jonstfrancis
Thank you Diana,
sharing your experience has been very helpful with my plans.
I appreciate your help